This joint report highlights opportunities for mobilizing investment for a sustainable blue economy in Asia and the Pacific, focusing on small and medium-sized enterprises (SMEs). SMEs' limited access to capital makes them the "missing middle" in sustainable blue economy development. This report proposes SME sector priorities in the blue economy, analyses the financing gap, and shares tools and resources to support new financial connections between international capital and local actors. It recommends the establishment of a new blended finance platform—SME Blue Impact Asia—to help fill the estimated $2 trillion SME blue economy financing gap in developing Asia.